Granulation and waves

Hirzberger, J.

doi:10.1002/asna.200310121

Cited by 3 publications

(3 citation statements)

References 54 publications

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“…This driver excites upwardly propagating ion and neutral acoustic waves (e.g., Zaqarashvili et al 2011). We set V 0 = 0.1 km s −1 , but allow P d to vary within the range of 5 s ≤ P d ≤ 300 s. These values fit to the typical characteristics of flow associated with the solar granulation (e.g., Musielak et al 1994;Hirzberger 2003). Among others Tu & Song (2013) and Arber et al…”

Section: Physical Modelmentioning

confidence: 99%

Heating of a Quiet Region of the Solar Chromosphere by Ion and Neutral Acoustic Waves

Kuźma

Wójcik

Murawski

2019

ApJ

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Using high-resolution numerical simulations we investigate the plasma heating driven by periodic two-fluid acoustic waves that originate at the bottom of the photosphere and propagate into the gravitationally stratified and partially ionized solar atmosphere. We consider ions+electrons and neutrals as separate fluids that interact between themselves via collision forces. The latter play an important role in the chromosphere, leading to significant damping of short-period waves. Long-period waves do not essentially alter the photospheric temperatures, but they exhibit the capability of depositing a part of their energy in the chromosphere.This results in up about a five times increase of ion temperature that takes place there on a time-scale of a few minutes. The most effective heating corresponds to waveperiods within the range of about 30-200 s with a peak value located at 80 s. However, we conclude that for the amplitude of the driver chosen to be equal to 0.1 km s −1 , this heating is too low to balance the radiative losses in the chromosphere.

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Section: Physical Modelmentioning

confidence: 99%

Heating of a Quiet Region of the Solar Chromosphere by Ion and Neutral Acoustic Waves

Kuźma

Wójcik

Murawski

2019

ApJ

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“…There is a great variety of MHD wave activity expected and observed in the inhomogeneous solar atmosphere. In addition to isolated MBP fluctuations, there is ambient acoustic wave energy excited by convection, shock steepening in the chromosphere and transition region, and both driven and free oscillations in sunspots and coronal loops (see recent reviews by Axford et al 1999;Roberts 2000;Bogdan 2000;Hirzberger 2003). A significant fraction of the Sun's magnetic flux may also be distributed outside the MBPs, network, and active regions (e.g., Schrijver & Title 2003), and acoustic waves in "field-free" regions may in fact be magnetoacoustic.…”

Section: Overall Picture Of Open Field Regionsmentioning

confidence: 99%

On the Generation, Propagation, and Reflection of Alfven Waves from the Solar Photosphere to the Distant Heliosphere

Cranmer

Ballegooijen

2005

ASTROPHYS J SUPPL S

431

590

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We present a comprehensive model of the global properties of Alfvén waves in the solar atmosphere and the fast solar wind. Linear non-WKB wave transport equations are solved from the photosphere to a distance past the orbit of the Earth, and for wave periods ranging from 3 seconds to 3 days. We derive a radially varying power spectrum of kinetic and magnetic energy fluctuations for waves propagating in both directions along a superradially expanding magnetic flux tube. This work differs from previous models in three major ways. (1) In the chromosphere and low corona, the successive merging of flux tubes on granular and supergranular scales is described using a two-dimensional magnetostatic model of a network element. Below a critical flux-tube merging height the waves are modeled as thin-tube kink modes, and we assume that all of the kink-mode wave energy is transformed into volume-filling Alfvén waves above the merging height. (2) The frequency power spectrum of horizontal motions is specified only at the photosphere, based on prior analyses of G-band bright point kinematics. Everywhere else in the model the amplitudes of outward and inward propagating waves are computed with no free parameters. We find that the wave amplitudes in the corona agree well with off-limb nonthermal line-width constraints. (3) Nonlinear turbulent damping is applied to the results of the linear model using a phenomenological energy loss term. A single choice for the normalization of the turbulent outer-scale length produces both the right amount of damping at large distances (to agree with in situ measurements) and the right amount of heating in the extended corona (to agree with empirically constrained solar wind acceleration models). In the corona, the modeled heating rate differs by more than an order of magnitude from a rate based on isotropic Kolmogorov turbulence.Subject headings: MHD -solar wind -Sun: atmospheric motions -Sun: corona -turbulence -waves of strong (1-2 kG) magnetic field believed to be contained within nearly vertical flux tubes (e.g., Sheeley

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“…Observing the Sun in white light outside active regions shows that the surface is dominated by a granular pattern of bright cells and dark lanes, created by the convective motion of the plasma (see left panel in Figure 1.4). The typical lifetime of these granular cells is around 10 minutes and their sizes are around 1 Mm (Hirzberger 2003). The cells are characterised by central upflows with velocities in the range of 1 km s −1 .…”

Section: Connection Between the Photosphere And Chromospherementioning

confidence: 99%

Slender Ca II H fibrils observed by SUNRISE/SuFI

Maranhas¹

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Granulation and waves

Cited by 3 publications

References 54 publications

Heating of a Quiet Region of the Solar Chromosphere by Ion and Neutral Acoustic Waves

Heating of a Quiet Region of the Solar Chromosphere by Ion and Neutral Acoustic Waves

On the Generation, Propagation, and Reflection of Alfven Waves from the Solar Photosphere to the Distant Heliosphere

Slender Ca II H fibrils observed by SUNRISE/SuFI

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